HOLY COW! Now that is something I've never had happen or heard of before but you know how it is in a world with horses! I wonder, just out of curiosity, if it was the EZ ride brand or another brand? Not all aluminum is created equal when it comes to hardware, obviously there are alloys - an alloy would be easier to bend or smash (sometimes).
Not sure on brand for the lady who mashed against a tree.
But I suspect there are a lot more people who have ridden in them with no issues (indeed, I did for a season and a half).